Multilayer interconnection structures for semiconductor device include a Cu interconnection (wiring) and interlayer insulating films. In the multilayer interconnections, a reduction in signal propagation speed is determined by the interconnection resistance and parasitic capacities between interconnections. In recent years, with increased packaging densities of semiconductor integrated circuits, interconnection width and interconnection pitch are becoming narrower, causing an increase in interconnection resistance and an increase in parasitic capacities. The volume of insulating films can be reduced by reducing the wiring thickness so as to reduce the cross-section area thereof. However, a reduction in wiring thickness causes a further increase in interconnection resistance, making it impossible to increase the response speed of semiconductor devices. Therefore, a reduction in electrical resistance of interconnections and a reduction in dielectric constant of insulating films are effective to achieve the increase in response speed. Further, it is expected that the reduction in electrical resistance of interconnections and reduction in dielectric constant of insulating films will be major factors that control the performance of semiconductor devices. However, when the amount of organic groups is increased to make insulating films have low dielectric constant, insulating films are hydrophobized, causing a decrease in adhesion of the insulating films.
As described above, when the adhesion between laminated insulating films decreases, film rupture occurs among these films, resulting in a reduction in yield and a decrease in reliability. To avoid this problem, there have been studied materials for enhancing the adhesion and methods using plasma, and ozone. However, the problem has not yet been adequately solved.
As described above, when interlayer insulating films having low dielectric constant are used in a multilayer interconnection, it is important to improve the adhesion between these films.
In addition, the technique for irradiating an electron beam to insulating films is disclosed.